package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWork;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;

import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestBody;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collection;
import java.util.Collections;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWork redisIdWork;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static{//提前准备好脚本
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }


    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while (true){
                try {
                    //1. 获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2. 创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }

    private IVoucherOrderService proxy;

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();//无参默认是30s
        if(!isLock){
            //获取锁失败，返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try{
            //获取代理对象（事务），不能在这里获取代理对象，因为底层也是从ThreadLocal里拿的
            //IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
            proxy.createVoucherNew(voucherOrder);
        }finally {
            //释放锁
            lock.unlock();
        }

    }

    @Transactional
    public void createVoucherNew(VoucherOrder voucherOrder){
        // 7.添加一人一单的逻辑
        Long userId = voucherOrder.getUserId();
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        if(count>0){
            log.error("用户已经购买过一次");
            return;
        }

        // 5.扣减库存
        boolean sucess = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                //.eq("voucher_id",voucherId/vourcher.getVoucherId())
                .gt("stock",0)//用乐观锁
                .update();
        if(!sucess){
            log.error("库存不足");
            return;
        }

        // 6.创建订单

        save(voucherOrder);


    }

    public Result seckillVoucherLua(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //1. 执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        //2.判断结果是为0
        int r = result.intValue();
        if(r!=0){
            //2.1.不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2.为0，有购买资格，把下单信息保存到阻塞队列
        //TODO 保存到阻塞队列
        // 6.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 6.1 订单id
        long orderId = redisIdWork.nextId("order");
        voucherOrder.setId(orderId);
        // 6.2 用户id
        //Long userId = UserHolder.getUser().getId();
        voucherOrder.setUserId(userId);
        //6.3 代金卷id
        voucherOrder.setVoucherId(voucherId);
        //2.6.放入阻塞队列
        orderTasks.add(voucherOrder);

        //获取代理对象
        proxy = (IVoucherOrderService)AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(orderId);
    }




    //-------------------------------------------
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠卷
        SeckillVoucher vourcher = seckillVoucherService.getById(voucherId);

        // 2.判断秒杀是否开始
        if(vourcher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀尚未开始");
        }
        // 3.判断秒杀是否结束
        if(vourcher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束");
        }
        // 4.判断库存是否充足
        if(vourcher.getStock() < 1){
            return Result.fail("库存不足");
        }


        Long userId = UserHolder.getUser().getId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();//无参默认是30s
        if(!isLock){
            //获取锁失败，返回错误或重试
            return Result.fail("不允许重复下单");
        }
        try{
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
            return proxy.createVoucher(voucherId);
        }finally {
            //释放锁
            lock.unlock();
        }

        //2. 自定义分布式锁
//        Long userId = UserHolder.getUser().getId();
//        SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate,"order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock(1200);
//        //判断是否获取锁成功
//        if(!isLock){
//            //获取锁失败，返回错误或重试
//            return Result.fail("不允许重复下单");
//        }
//        try{
//            //获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
//            return proxy.createVoucher(voucherId);
//        }finally {
//            //释放锁
//            lock.unlock();
//        }

        //1. 单体
//        Long userId = UserHolder.getUser().getId();
//        synchronized (userId.toString().intern()){
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
//            return proxy.createVoucher(voucherId);
//        }

    }

    @Transactional
    public Result createVoucher(Long voucherId) {

        // 7.添加一人一单的逻辑
        Long userId = UserHolder.getUser().getId();
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        if(count>0){
            return Result.fail("用户已经购买过一次");
        }

        // 5.扣减库存
        boolean sucess = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                //.eq("voucher_id",voucherId/vourcher.getVoucherId())
                .gt("stock",0)//用乐观锁
                .update();
        if(!sucess){
            return Result.fail("库存不足");
        }

        // 6.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 6.1 订单id
        long orderId = redisIdWork.nextId("order");
        voucherOrder.setId(orderId);
        // 6.2 用户id
        //Long userId = UserHolder.getUser().getId();
        voucherOrder.setUserId(userId);
        //6.3 代金卷id
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);

        return Result.ok(voucherOrder);
    }


}
